/(?i)\u0149\u0149/ =~ "\u0149\u0149" doesn't match (Issue #40)

'\u0149' is casefolded into '\u02bc' + 'n'.  They were compiled into
'exactn-ic:\xca\xbc' + 'exact1-ic:n'.  One character was divided into
two opcodes, so it couldn't match to a character '\u0149'.
Merge a series of 'exactn-ic' and 'exact1-ic' into one 'exactn-ic'.
Add test for issue #40